Universities across China are tightening controls on student-run Internet discussion forums as part of a Communist Party campaign to strengthen what it calls "ideological education" on campuses. The crackdown has caused widespread resentment among students and prompted at least two demonstrations in recent days.

The Web sites, which run on school computer networks, host some of China's largest and liveliest online bulletin boards. They serve as virtual meeting places where millions of educated Chinese across the country gather for discussions about everything from pop culture to politics.

But in recent weeks, universities have started blocking off-campus users from participating, including alumni and students and faculty from other universities, according to students and college officials. They have also begun requiring students to register with their real names when going online, eliminating the anonymity that allowed participants to speak without fear of punishment by the authorities.

The new restrictions come during a general tightening of controls on the Chinese media by the party's propaganda authorities, who have struggled to control debate on the Internet and have viewed university Web sites with particular concern because they allow students from across the country to easily communicate with one another.

Censorship on university sites has been slower and less heavy-handed than on commercial sites, and liberal scholars have used them to distribute sharp critiques of the Communist Party and to call for political reform.

College officials and students involved in managing the sites said the Education Ministry ordered schools to impose the latest restrictions in January as part of a national campaign to ensure that students did not challenge the party's rule.

An official at Beijing University said it had not applied the "real-name policy yet. . . . We're still waiting for further instructions." He acknowledged that students were upset, but said the school had not given them an explanation.

A propaganda official at Jiaotong University in Shanghai confirmed that the school "was adopting measures to clean the Web" by the end of March. A spokesman for the Education Ministry declined to comment.

The effort appears to have provoked a backlash among students. On Tuesday, one student disrupted a discussion at Beijing University to speak out against the new restrictions, kneeling and bowing several times when the moderator refused to call on him. The panelists, members of a national government advisory congress, intervened and heard the student out, according to one witness and accounts by others posted on the Internet.

The incident followed a rare demonstration Friday at neighboring Tsinghua University, where about 100 students gathered around a stone monument engraved with the motto, "Actions are greater than words," and covered it with paper cranes and other origami figures to urge the school to rescind the new policies, witnesses said.

Another demonstration took place on Tuesday at Nanjing University west of Shanghai, where more than 200 students participated in an evening vigil around a campus fountain, students said.

The Internet bulletin boards at Tsinghua and Nanjing universities were the largest student-run discussion sites in the country. Authorities began blocking outsiders from reading or leaving messages on the Tsinghua site last week and have shut down the Nanjing site. Students confirmed that similar restrictions were put in place at universities in Shanghai, Tianjin, Xian, Hangzhou, Jilin, Wuhan and Guangzhou.

Tsinghua University officials responded to the demonstration by holding an emergency meeting and promising to appeal to the Education Ministry to loosen the restrictions. But students said they did not expect the party to back down, in part because most students were too frightened of being expelled to participate in protests.

"There's no hope at all. The bulletin board era is over," said one student who resigned as a Web site manager and spoke on condition of anonymity. "Student leaders opposed the policy, but college officials said they were following orders from above and asked, 'Would you be happier if the site was shut down completely?' "

Many students used the Internet to express their anger at the Chinese leadership. "By locking up young students, separating them and monitoring them, they will lose the people's hearts," wrote one student at Tsinghua.

"I just can't figure it out," wrote another student at Beijing University. "Why do policymakers use the most indiscreet and stupid methods, which does nothing to help them and instead sets the young elite against them?"

The new policies have prompted anger off campus as well. Editors at three state-owned newspapers have risked punishment by printing critical reports about the crackdown, with one tabloid publishing an editorial headlined, "Universities Should Not Build Walls Around the Internet."

"As the users of the bulletin board, we have rights. And as graduates of Tsinghua, we feel we should do something," said Tang Yang, 28, a computer engineer. "Our goal is to arouse more people, especially Tsinghua graduates off campus, and let them know what we've lost."

Tang said he managed to access the Tsinghua bulletin board and post a note urging people to contact him if they were interested in helping. More than a dozen people sent e-mails, Tang said, but then his note was deleted.